docs: def umount(self, all=False, force=True):
          """
          unmount container filesystem
          :param all: bool, option to unmount all mounted containers
          :param force: bool, force the unmounting of specified containers' root file system
          :return: str, the output from cmd
          """
          # FIXME: handle error if unmount didn't work
          options = []
          if force:
              options.append('--force')
          if all:
              options.append('--all')
          cmd = ["podman", "umount"] + options + [self.get_id() if not all else ""]
          return run_cmd(cmd, return_output=True)